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Transporte de cádmio em células branquiais do caraguejo de mangue Ucides cordatus / Cadmium transport in gill cells of the mangrove crab Ucides cordatusPriscila Ortega 04 July 2012 (has links)
O Ucides cordatus é um caranguejo que habita mangues. Estas regioes podem ser contaminadas com o cádmio, através de dejetos de indústrias e descarte de pilhas e baterias, atingindo o animal por meio de suas brânquias. Assim, o objetivo da dissertação foi verificar a cinética de transporte do cádmio com o uso de inibidores específicos, e sua interação com o cálcio, zinco e ATP. Para isso, as brânquias foram separadas em anteriores e posteriores, e as células foram dissociadas pelo método de dissociação enzimática; a seguir, as células foram marcadas com Fluo 3 am e realizada a cinética de transporte no espectrofluorímetro, adicionando-se concentrações de 0,5, 1,0 e 1,5μM de sulfato de cádmio (CdSO4), cloreto de cádmio (CdCl2), cádmio + cálcio, cádmio + zinco, cálcio e zinco para verificar a interação do Cd com cálcio ou zinco. Posteriormente, houve a adição dos inibidores como vanadato, amilorida, ouabaina e BAPTA às células, e, novamente, efetuou-se o transporte de cádmio nas concentrações 0,5, 1,0 e 1,5μM. Em seguida, adicionou-se ATP e efetuou-se o transporte de cádmio nas mesmas concentrações citadas anteriormente. Os resultados mostraram um transporte de cádmio sigmoidal, quando em presença de CdSO4, e um pico de 5 segundos de entrada de cádmio e uma posterior queda, quando em presença de CdCl2; além de uma provável competição entre o cádmio e o cálcio e entre o cádmio e o zinco. Observou-se também uma efetiva ação dos inibidores, indicando que o cádmio possivelmente entrou na célula através de canais de cálcio, trocadores Na+/H+ e trocadores aniônicos dependentes ou não de Na+. Percebeu-se ainda que o ATP não influenciou na entrada de cádmio, ou seja, aparentemente não existe uma Cd ATPase nas células branquiais de Ucides cordatus / Ucides cordatus is a crab that lives in mangroves. These regions may be contaminated with cadmium by industrial wastes and disposal of batteries, reaching the animal through its gills, being a toxic metal. The aim of the study was to investigate the kinetics of cadmium transport using specific inhibitors, and its interaction with calcium, zinc and ATP. For this, the gills were separated in anterior and posterior regions, and their cells were dissociated by enzymatic dissociation. After, the cells were labeled with Fluo 3 am and the kinetics of transport of cadmium were performed in a spectrofluorimeter by adding CdSO4 and CdCl2 at concentrations of 0.5, 1.0 and 1.5μM. For the interaction experiments Cd was added as, cadmium + calcium, cadmium + zinc, calcium and zinc alone. A subsequent experiment, addition of inhibitors such as vanadate, amiloride, ouabain and BAPTA were performed, and again, the transport of cadmium was studied at concentrations of 0.5, 1.0 and 1.5 μM. Then, ATP was added and the transport of cadmium was performed in the same concentrations mentioned above. Results showed a sigmoidal curve, when in presence of CdSO4, and a peak of 5 seconds for cadmium uptake and a posterior decline when in the presence of CdCl2. In addition, probably occurred a competition between calcium and cadmium and between cadmium and zinc, and here was also an effective action of some inhibitors, indicating that cadmium probably entered the cell by calcium channels, Na+/H+ exchangers and exchangers anionic inorganic dependent of Na+ or not. ATP had no effect for cadmium influx, suggesting that there is no Cd ATPase present in gill cells of Ucides cordatus
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Some aspects of polarisation transfer in NMR spectroscopyKoskela, H. (Harri) 02 August 2005 (has links)
Abstract
Modern NMR methods in liquids are based on the transfer of polarisation from nucleus to nucleus to generate multidimensional heteronuclear correlation spectra. The factors that influence the efficiency of heteronuclear polarisation transfer in multi-pulse experiments, and in that way the quality of spectra are the subject of this thesis. The flow of coherence through pulse sequences can be designed and analysed with the aid of product operator calculations. Results of the study include improvements to quantitative two-dimensional shift-correlated experiments, and demonstration of the benefits of closely spaced 180° pulse trains in polarisation transfer steps in long-range correlation experiments and isotope editing filters.
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Poverty dynamics and livelihood challenges among small-scale fishing communities on lake Kariba - ZimbabweMushongera, Darlington D. January 2013 (has links)
Magister Philosophiae - MPhil / Poverty dynamics and livelihood challenges among small-scale fishing communities on
Lake Kariba (Zimbabwe)
The aim of this study was to assess poverty among small-scale fishing communities on Lake
Kariba (Zimbabwe) as well to as identify livelihood challenges that confront them. Two
fishing communities were used as case studies and were uniquely selected from among the
many fishing camps/villages dotted along the Zimbabwean shoreline of Lake Kariba.
Depending on gear type, fishing activities on Lake Kariba target both the smaller-sized
Kapenta species and larger species such as the bream and the tiger. Fishing activities are a
major livelihood source for fishers in the two case studies upon which they obtain food and
derive income to address other family needs. Mutual linkages and exchanges also exist
between fishing camps/villages and communal areas where land-based activities such as
cropping and livestock rearing are carried out.
Before fieldwork, there was a pre-conceived notion that members of fishing communities on
Lake Kariba were very poor. Although the fishers expressed desires for a better life than they
were experiencing, they did not consider themselves poor. Instead, they rated their economic
position as well off compared to some of their urban counterparts. However, on further
interrogation, the study revealed that the fishers were facing a set of vulnerabilities that is
commonly associated with the fishing profession. These vulnerabilities had substantial
impacts on the livelihood system of these fishers. Using vulnerability ladders, a picture was
painted depicting the severity of these vulnerabilities. It emerged that fishers were more
vulnerable to existing state institutions that are designed to manage access to and the use of natural resources in the country. There are several reasons to suggest why this is the case
which include, (i) the high cost of accessing the fishery, (ii) the stern measures in place that
restrict access to and use of the fishery, and (iii) the punitive measures imposed for
contravening rules of access and use of the fishery.
Although restricting access is in line with the principle of long run sustainability of the
fishery, it may threaten the development of the fishing industry and impact negatively on
livelihoods of communities involved. Unlike fisheries elsewhere in the world, Lake Kariba is
not viewed as a vehicle for reducing poverty and achieving food security. On the contrary,
government places emphasis on preserving and enhancing the natural environment both
aquatic and non-aquatic with a view to sustaining tourism. Under such a paradigm, fishing is
viewed as a threat to the natural environment and requires strict management. Heavy fines are
therefore imposed on users that violate the rules of access. Many of the fishers have had their
properties attached after failing to raise the necessary amounts to cover the fines.
By shifting away from the promotion of fisheries, government has accelerated the decline of
the small-scale fishing industry on Lake Kariba, through narrowing the fishers action space
and creating an environment conducive for corruption. The decline has subsequently shrunk
the livelihoods base of local communities as well as many others who are associated with the
fishing industry. While the sustainability of the fishery is paramount, government needs to
reconsider its strategy on governing and managing fisheries on Lake Kariba. Given enough
support, small-scale fisheries on Lake Kariba have the potential to contribute significantly to
the country’s Gross Domestic Product. Small-scale fisheries have also proved their resilience
in the wake of the severe economic crisis that Zimbabwe experienced between 2007 and
2009. During this period, there were widespread shortages of basic food items in the country and the demand for fish and fish products rose drastically. The fishers reported that there was
an increase in the demand for fish during the crisis period to the extent that they could not
supply enough to satisfy the market. This supports the observation by the United Nations
(2010) that fisheries, in particular small-scale, can play an important role in the economy in
terms of livelihoods, poverty reduction and food security. Fishing activities are also the
perfect complement to other land-based livelihood activities for communities that live in
close proximity to large water bodies.
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The Effects of the Heme Oxygenase-1/Carbon Monoxide System on Cardiorespiratory Control in FishTzaneva, Velislava January 2016 (has links)
Endogenously produced carbon monoxide (CO) is an important gaseous signalling molecule which regulates a variety of cardiorespiratory functions. CO is produced in cells by the heme oxygenase (HO) family of proteins by the breakdown of heme into equimolar amounts of CO, bilirubin and Fe2+. My thesis focuses on the hypoxia- and hyperoxia-inducible HO-1/CO system exclusively and aims to provide the first evidence that the HO-1/CO system is involved in cardiorespiratory control in the zebrafish (Danio rerio) and goldfish (Carassius auratus). Overall, I hypothesise that the HO-1/CO system acts as a negative regulator of cardiorespiratory function in fish. Using immunohistochemistry, I was able to characterise the distribution of HO-1 and thus reveal the potential for endogenous CO production (from heme breakdown) in branchial and skin neuroepithelial cells (NECs; putative O2 chemoreceptors) and associated innervation as well as the heart of the developing zebrafish larva. The presence of HO-1 in these structures suggests the likelihood of specific and localized production of CO in fish. To assess the functional significance of the HO-1/CO system in control of cardiorespiratory function, I used pharmacological and gene knock down approaches to diminish HO-1 activity, and presumably endogenous CO production, in adult and larval fish, respectively. The results from these experiments provided evidence that 1) CO has an inhibitory influence on ventilation in goldfish and zebrafish but that its function is temperature- and species-dependent and 2) showed that the HO-1/CO system tonically inhibits cardiac activity in larval zebrafish.
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Den feministiska rakhyveln : En kvalitativ studie av marknadsfeministiska tendenser i Estrids kommunikationBurlin, Amanda, Karlsson, Petra January 2020 (has links)
The use of feminist messages in marketing is not a new phenomenon. However, there has been an increase in using this as a strategy in later years. Estrid is a Swedish company that sells a razor subscription service with an entire marketing strategy based on using feminist messages. This contradictory paradox motivated this thesis' subject and aim: to examine how young women interpret feminist messages in parts of Estrid's communication, and to critically discuss the use of a feminist strategy in communication from a company that sells razors to women from the perspective of commodity feminism according to Rosalind Gill. The research questions are thereby: 1) Can Rosalind Gill's aspects of commodity feminism be identified in parts of Estrid's communication? If so, how?; 2) How does young women interpret the feminist messages in parts of Estrid's communication?To answer the purpose statement, a semiotic analysis was conducted with pictures derived from Estrid's website. Two focus groups with women in the ages 20–25 was held to get the perspective from a potential target group. The material was then analyzed through the lens of commodity feminism. Through this analysis we could identify the use of multiple of Rosalind Gill's aspects of commodity feminism through different semiotic connotations in the material, as well as in the commentary from the focus groups. Further, the study demonstrated a feeling of internal ambivalence amongst the focus group participants. On the one hand, everyone showed a positive attitude towards Estrid including diverse models and body hair in their advertisements. On the other hand, they were all skeptical towards the genuinity of the feminist messages included in the same material. What inspired this thesis was therefore present in all stages throughout it: the paradox of selling razors using feminist messages.
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Under Rosen : IB: Nationell säkerhetstjänst, Politisk polis eller Stat i staten?Hjelm, Markus January 2023 (has links)
Civilian control over military forces is a prerequisite within democracies in the study of civil-military relations. This requirement extends to military intelligence, as they are a part of the military. However, this relationship needs to balance secrecy with transparency concerns, a relationship which can prove difficult. In Sweden during the 1970’s, this discussion came to a fore when the intelligence organisation IB was revealed to the public. This sparked an ongoing debate within the academic community regarding the limits of intelligence organisations authority, their need for secrecy and the government’s ability to control them. This thesis aims to investigate IB and the government’s control over it during 1965-1973, the years it operated as the sole military intelligence organisation in Sweden. With perspectives derived from Peter Gills thoughts on intelligence control and oversight, this thesis examines the mechanism of intelligence control and inquiry that were present in Sweden during the relevant timeframe. The findings are then judged with Gill’s concepts as a framework, in order to evaluate IB´s role as an intelligence organisation within a liberal democracy. These findings will thereafter be compared with the image of IB as presented by leading contemporary politicians and intelligence commanders, in order to give nuance to the findings. The thesis will show, with support of the theory and methodology, that IB can’t be described as a national intelligence agency, but as a political police. Its lack of transparency, secret existence and politicly motivated goals are the main reasons for this result. The absence of key mechanism of control as described by Gill, made it impossible for the organisation to be controlled, with some reservations for the ruling party’s ability to do so. It also contextualises these findings with the presented opinions of the contemporary actors. These results shed new light on intelligence accountability during the cold war in Sweden. It also reaffirms previous findings on IB with the use of new perspectives. The Thesis provides another lens to view Swedish intelligence history through and contributes to that field of history.
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Ionoregulatory Physiology of the African Lungfish, Protopterus dolloi and Protopterus annectensPatel, Monika 12 1900 (has links)
<p> The origin of terrestrial vertebrates from water-dependent fish involved numerous
morphological and physiological modifications (Benton, 1990). Interest in the adaptive mechanisms involved in the transition from aquatic to terrestrial environments has led to
research involving lungfish. African lungfish are obligatory air breathers and have a primitive lung and characteristically underdeveloped gills compared to freshwater teleosts. The gills are thought to play an important role in CO2 excretion and possibly in water and ionic exchange while in aquatic conditions. At present, little is known about the basic ionoregulatory physiology of lungfishes; the aim of this thesis was to describe the basic principles of ion and water balance in two species of African lungfish, Protopterus dolloi and Protopterus annectens. Patterns and rates are very similar in the two species, apart from differences in water handling at the kidney. In aquatic conditions, plasma ion (Na+, Cl-, Ca2+) levels are lower than in teleost fish. The major site of diffusive water exchange appears to be the gills. The skin is well vascularized and also serves as site of water exchange, and likely Cl- and Ca2+ uptake as well. However, water and ion exchange rates are lower than in freshwater teleosts, probably due to the reduced gill area, though glomerular filtration, urine flow rates (an index of osmotic permeability), and urinary ion excretion rates are comparable to those of teleosts. Water exchange rates increase immediately after feeding, likely associated with specific
dynamic action, and decrease with prolonged terrestrialization, likely due to disturbances in gill function. A budget analysis of ion balance indicates that both unidirectional uptake from the water and net uptake from the food (especially for Cl-) are important, whereas unidirectional efflux across the gills and/or skin is a larger route of ion loss than are feces or urine. Despite many physiological differences between freshwater teleosts and the African lungfish, water and ion balance are maintained in a broadly similar fashion and are achieved by compensating for the reduced gill area by ion acquisition via the skin and by greater ion reabsorption by the kidneys.</p> / Thesis / Master of Science (MSc)
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Könsmaktsordningen, fortfarande ett problem idagens medier? : Semiotisk bild- och textanalys av livsstilsmagasinen Veckorevyns och Café 2017Nilsson, Alexandra January 2018 (has links)
Livsstilsmagasinen Café och Veckorevyn sägs fungera som inspiration för läsaren till att förbättra sitt liv och illustrera hur kvinnor och män ska se ut och vara. Idealet som tidningarna bygger upp i bild och text är däremot endast en normativ värdering av hur kvinnor och män bör vara. utifrån det samhälle som vi lever i idag - ett samhälle där vår vardag präglas av olika stereotypa ideal, där det skapats ett “vi och dom tänk”. Det är dessa bilder som ses återkommande i det virtuella medielandskapet, som uppvisar en begränsad syn av kvinnor och män, vilket ger upphov till gruppering bland individer. Uppsatsen behandlar hur bilden av kvinnligt och manligt återskapas utefter de normer som redan existerar. De livsstilsmagasin som användes till studien representerar genus och könsmaktsordningen och studiens material består av 13 stycken omslagsbilder från de två ledande livsstilsmagasinen i Sverige. Bilden av kvinnligt och manligt och det som kallas könsmaktsordning grundar sig på ett västerländskt synsätt att se på ideal och resultatet vill hur pass tydligt detta förekommer och även påvisa att om idealet bevarats i detta material också förespråkar en enhetlig och normativ bild av kön. Syftet med denna uppsats är att genom semiotisk bildanalys titta på hur Veckorevyns och Cafés omslagsbilder under 2017 och januari 2018 upprätthåller könsmaktsordningen.
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Problems for Michael Gill’s semantic pluralism : The ostensibility of certain moral agreements and disagreementsEngström, Simon January 2020 (has links)
This paper concerns the semantic branch of meta-ethics, and examines a version of so called semantic pluralism advocated by Michael Gill. Briefly put, Gill suggests that ordinary people’s usage of moral terms is rather messy in the sense that the meaning of moral terms can vary not only between different people, but also for one and the same person in different contexts. Such variability in word-meaning is explained by his assumption that people’s meta-ethical commitments are part of their moral thought and language, which is to say that their meta-ethical commitments have implications for the meaning of moral terms. In this paper I pursue two objectives. The first is exegetical and aim to clarify how Gill’s semantic pluralism in general, and his Indeterminacy- and Variability theses in particular, are intended to be understood—specifically in relation to the cognitivist/non-cognitivist debate. The second objective is argumentative. I first present and evaluate an objection to Gill’s semantic pluralism from Walter Sinnott-Armstrong who argue that Gill’s Variability thesis implies that interlocutors with different meta-ethical commitments are talking past each other rather than having genuine first order moral agreements and disagreements. I then argue that a similar problem occurs also for certain second order moral disagreements, particularly those in which moral terms are used rather than mentioned. I then argue that this is problematic not only on independent grounds, but also because it is inconsistent with the very assumptions Gill makes to support his view. My argument therefore appears forceful by Gill’s own lights. Combined, Sinnott-Armstrong’s objection and my own leads me to conclude that Gill’s semantic pluralism does not look promising.
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Caracterização cinética da (Na, K)-ATPase da fração microsomal do tecido branquial do ermitão intertidal Clibanarius vittatus / Kinetic characterization of gill microsomal (Na+,K+)- ATPase from intertidal hermit crab Clibanarius vittatusSivieri, Rubia Regina Gonçalves 23 March 2007 (has links)
A (Na+,K+)-ATPase presente no tecido branquial dos crustáceos osmorreguladores é um componente essencial do sistema de regulação iônica e osmótica e de excreção ativa de NH4 +. Dessa forma, a caracterização cinética da (Na+,K+)-ATPase branquial de Clibanarius vittatus pode fornecer dados importantes para a compreensão dos mecanismos bioquímicos desses processos. Nesse sentido, foram realizados ensaios cinéticos com a fração microsomal obtida do tecido branquial de C. vittatus. Os dados obtidos revelaram a presença de um único pico com atividade ATPase. Os dados obtidos a partir da hidrólise do substrato ATP revelaram a presença de dois sítios, um de alta afinidade que apresenta interação sítio-sítio (nH=1,9; K0,5= 63,8 ± 2,9 nM e V= 19,1 ± 0,8 U/mg) e outro de baixa afinidade, com características Michaelianas (nH=1,0; KM= 44,1 ± 2,6 mM e VM= 123,5 ± 6,1 U/mg). Além disso, foi observada interação do tipo sítio-sítio (nH= 1,8) para estimulação dos íons magnésio (V= 132,0 ± 5,3 U/mg e K0,5= 0,36 ± 0,02 mM). Por outro lado, as interações dos íons sódio (K0,5= 7,4 ± 0,4 mM), potássio (K0,5= 1,51 ± 0,05 mM) e amônio (K0,5= 4,5 ± 0,2 mM) obedeceram a uma cinética Michaeliana. Os dados obtidos mostraram que em condições saturantes de íons potássio, a atividade enzimática aumenta de maneira concentração-dependente quando na presença de íons amônio (V= 290,8 ± 14,4 U/mg e KM= 2,9 ± 0,1 mM). A presença da ouabaína no meio reacional acarretou 66% de inibição (KI= 117,3 ± 3,5 mM), indicando a presença de outras ATPases. A atividade K+-fosfatase, medida usando o substrato sintético PNFF revelou a presença de um único sítio de hidrólise (V= 47,4 ± 1,9 U/mg e KM= 1,0 ± 0,04 mM) com características Michaelianas (nH= 1,1). Entretanto, para os íons Mg2+ (nH= 2,6 e K0,5= 0,6 ± 0,1 mM), K+ (nH= 1,4 e K0,5= 3,7 ± 0,1 mM) e NH4 + (nH= 1,9 e K0,5= 19,3 ± 0,7 mM) foram observadas interações sítio-sítio. Em conjunto, os resultados cinéticos obtidos para a (Na+,K+)-ATPase branquial de C. vittatus, reforçam a possibilidade de que essa enzima contribui eficientemente com o mecanismo adaptativo desencadeado em resposta à exposição a altas concentrações externas de amônia. É importante ressaltar que o presente trabalho representa o primeiro estudo de caracterização cinética da enzima (Na+,K+)- ATPase no ermitão C. vittatus, um animal inserido em um microambiente constituído pela concha. Finalmente, este trabalho agrega informações relevantes relacionadas ao grupo dos Decapoda, em relação ao papel da (Na+,K+)-ATPase nos processos metabólicos e de osmorregulação nos crustáceos. / (Na+,K+)-ATPase is an essential component of osmotic and iono-regulatory system of crustacean gill and plays a relevant role in NH4 + excretion. Thus, the kinetic characterization of Clibanarius vittatus gill microsomal (Na+,K+)-ATPase, can provide crucial data to the understanding of osmoregulating and excretion processes of these animals in different environments, especially the shell microenvironment. In this way, kinetic assays were performed with gill microsomal fraction. The results showed a single protein peak with ATPase activity. The results from ATP hydrolysis revealed the presence of two different sites. One of them is related to the high-affinity with site-site interaction (nH=1.9; K0.5= 63.8 ± 2.9 nM and V= 19.1 ± 0.8 U/mg) and the other shows low-affinity, obeying Michaelis-Menten kinetics (nH=1.0; KM= 44.1 ± 2.6 mM and VM= 123.5 ± 6.1 U/mg). Moreover, site-site interaction (nH= 1.8) was observed to the magnesium ions stimulation (V= 132.0 ± 5.3 U/mg and K0.5= 0.36 ± 0.02 mM). On the other hand, the stimulations of Na+ (K0.5= 7.4 ± 0.4 mM), K+ (K0.5= 1.51 ± 0.05 mM) and NH4 + (K0.5= 4.5 ± 0.2 mM), followed Michaelis-Menten kinetics. At saturating concentrations of potassium ions, the enzyme activity was increased in a dependent-concentration manner with increasing ammonium ions concentration (V= 290.8 ± 14.4 U/mg and KM= 2.9 ± 0.1 mM). Ouabain inhibited 66% of (Na+,K+)-ATPase activity (KI= 117.3 ± 3.5 mM) of the gill microsomal enzyme, indicating the presence of other ATPase activities. The K+-fosfatase activity was also measured using PNPP, a synthetic substrate. PNPP hydrolysis resulted in single site hydrolysis site, obeying the Michaelis-Menten kinetics (nH= 1.1). However, it was observed site-site interactions for Mg2+ (nH= 2.6; K0.5= 0.6 ± 0.1 mM), K+ (nH= 1.4; K0.5= 3.7 ± 0.1 mM) and NH4 + (nH= 1.9; K0.5= 19.3 ± 0.7 mM) ion estimulations. Taken together, these results provide important informations on the kinetic properties of gill (Na+,K+)-ATPase of C. vittatus, emphasizing the synergiistic stimulation induced by K+ and NH4 +, which appear to contribute to the efficient adaptive mechanism triggered by exposure of high external ammonia concentrations. It is important to emphasize that this is the first study on the kinetic properties of (Na+,K+)-ATPase enzyme of the hermit crab C. vittatus. Finally, this study provide information concerning the (Na+,K+)-ATPase role in the metabolic and osmoregulating mechanisms of this Decapoda group
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